i did this myself on my last escort , but a thing well worth noticing is that you cant do more than 1 spot weld at a time.. 1 spot and wait for about 3 minutes, then do another.. if you do it much faster than this it will warp.. a mate of mine had a real shitter with rust in the roof for a while so we tried to weld his roof before we did mine so we learned a couple of things on that project.. but as long as it gets too cool properly it's not a problem..